Plants that are heterozygous for genetic markers but do not produce segregating progeny may be suspected of carrying a mutation conditioning apomixis. Seed stocks in which heterozygous plants could be identified phenotypically were treated with a chemical mutagen. These seed stocks were heterozygous for recessive genetic markers, and/or heterozygous for a chromosome translocation. Spikes from heterozygous M1 plants were harvested and seeded in bulk. Spikes from heterozygous M2 plants were harvested and planted in M3 rows. The M3 rows were observed for the absence of segregating progeny and/or were observed cytologically for the presence of a heterozygous translocation. M3 rows not segregating for the genetic markers were crossed onto plants homozygous for the genetic markers. The F1 progenies were observed for an expected ratio of 1 normal: 1 recessive plant. All nonsegregating lines were found to be non-heterozygous. These lines most likely occurred due to seed and pollen contamination or were the result of crossing over between genetic markers. Fertile M2 plants were harvested from the treated heterozygous translocation seed stock. Normally, barley plants heterozygous for a translocation will produce semisterile spikes. Plants that would normally be semisterile but are fertile could be carrying a mutation conditioning apomixis. Progeny of the fertile M2 plants were examined cytologically for the presence of the heterozygous translocation. All selected lines contained the normal seven pairs of chromosomes and were the result of seed or pollen contamination. Seed stocks which could eliminate the problem of contamination in future experiments were developed and discussed. Haploviable mutants closely linked with the male sterile locus, msg2, were isolated in these seed stocks. Haploviable mutants are recognized by upset genetic ratios of alleles linked with the mutant. Selfed progenies of plants carrying a haploviable mutation contained fertile and male sterile plants in about a 1:1 ratio. Mostly male sterile progenies were obtained when plants heterozygous for the haploviable mutant and the male sterile allele were crossed onto male sterile plants. Four lines containing haploviable mutants were evaluated for their usefulness in producing all male sterile lines for hybrid barley production.

Plants that are heterozygous for genetic markers but do not produce segregating progeny may be suspected of carrying a mutation conditioning apomixis. Seed stocks in which heterozygous plants could be identified phenotypically were treated with a chemical mutagen. These seed stocks were heterozygous for recessive genetic markers, and/or heterozygous for a chromosome translocation. Spikes from heterozygous M1 plants were harvested and seeded in bulk. Spikes from heterozygous M2 plants were harvested and planted in M3 rows. The M3 rows were observed for the absence of segregating progeny and/or were observed cytologically for the presence of a heterozygous translocation. M3 rows not segregating for the genetic markers were crossed onto plants homozygous for the genetic markers. The F1 progenies were observed for an expected ratio of 1 normal: 1 recessive plant. All nonsegregating lines were found to be non-heterozygous. These lines most likely occurred due to seed and pollen contamination or were the result of crossing over between genetic markers. Fertile M2 plants were harvested from the treated heterozygous translocation seed stock. Normally, barley plants heterozygous for a translocation will produce semisterile spikes. Plants that would normally be semisterile but are fertile could be carrying a mutation conditioning apomixis. Progeny of the fertile M2 plants were examined cytologically for the presence of the heterozygous translocation. All selected lines contained the normal seven pairs of chromosomes and were the result of seed or pollen contamination. Seed stocks which could eliminate the problem of contamination in future experiments were developed and discussed. Haploviable mutants closely linked with the male sterile locus, msg2, were isolated in these seed stocks. Haploviable mutants are recognized by upset genetic ratios of alleles linked with the mutant. Selfed progenies of plants carrying a haploviable mutation contained fertile and male sterile plants in about a 1:1 ratio. Mostly male sterile progenies were obtained when plants heterozygous for the haploviable mutant and the male sterile allele were crossed onto male sterile plants. Four lines containing haploviable mutants were evaluated for their usefulness in producing all male sterile lines for hybrid barley production.

en_US

dc.type

text

en_US

dc.type

Dissertation-Reproduction (electronic)

en_US

dc.subject

Barley -- Genetics.

en_US

dc.subject

Apomixis.

en_US

dc.subject

Plant mutation.

en_US

thesis.degree.name

Ph.D.

en_US

thesis.degree.level

doctoral

en_US

thesis.degree.discipline

Plant Sciences

en_US

thesis.degree.discipline

Graduate College

en_US

thesis.degree.grantor

University of Arizona

en_US

dc.contributor.advisor

Briggs, Rober E.

en_US

dc.contributor.advisor

Ramage, Robert T.

en_US

dc.contributor.committeemember

Dobrenz, Albert K.

en_US

dc.contributor.committeemember

Voigt, Robert L.

en_US

dc.contributor.committeemember

Endrizzi, John E.

en_US

dc.identifier.proquest

8814224

en_US

dc.identifier.oclc

701108001

en_US

All Items in UA Campus Repository are protected by copyright, with all rights reserved, unless otherwise indicated.